Crossbar latch

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The cross-bar latch is a technology created by Hewlett-Packard in February of 2005. This technology has the power to possibly replace the transistor.

Transistors are currently the main component in the processors of all electronic devices. The most important problem solved by this item in both low and high complexity electronics, from calculators to microcomputers, is that of switching. Voltage on the input terminal allows current to pass through the other two terminals. First attempted with vacuum tubes, the incredible advance in speed and size within computers has been attributed to the transistor, which could be created simply and easily and in a miniature fashion.

The crossbar was introduced by Hewlett-Packard scientists in the Journal of Applied Physics, and allows much the same functionality of transistors, except on a molecular scale. It has been seen by many as an advancement as far above the transistor as the latter was to the vacuum tube. The crossbar latch consists of a signal line crossed by two control lines. Depending on the voltages sent down the various lines, it can simulate the action of the three major logic gates: AND, OR and NOT.

The abstract of the patent is as follows: “A molecular crossbar latch is provided, comprising two control wires and a signal wire that crosses the two control wires at a non-zero angle to thereby form a junction with each control wire. Each junction forms a switch and the junction has a functional dimension in nanometers. The signal wire selectively has at least two different voltage states, ranging from a 0 state to a 1 state, wherein there is an asymmetry with respect to the direction of current flow from the signal wire through one junction compared to another junction such that current flowing through one junction into (out of) the signal wire can open (close) while current flowing through the other junction out of (into) the signal wire can close (open) the switch, and wherein there is a voltage threshold for switching between an open switch and a closed switch. Further, methods are provided for latching logic values onto nanowires in a logic array, for inverting a logic value, and for restoring a voltage value of a signal in a nano-scale wire. Invented by Phillip J Kuekes.”